Up to now, the only fast Light Emitting Diodes (LEDs) available are volume emitters. The output power of these volume-emitting LEDs is increased by a Bragg reflector at the rear side or at both sides (e.g., resonant cavity LED). Volume emitters are somewhat limited in that they will always have a larger form factor than their thin-film counterparts.
In the meantime, the progress at High Brightness LEDs (HB-LEDs) is enormously high. These HB-LEDs are designed for use in illumination, specifically in fields of use such as: light bulb replacement; automotive bulbs; and backlighting for flat screen televisions and projectors. All of these high output power LEDs are based on the thin-film manufacturing process. A significant disadvantage to using thin-film LEDs is that they are extremely slow in time behavior. The red thin-film LEDs (e.g., approximately 650 nm) are especially slow. Accordingly, the thin-film LEDs are severely limited in that they can only be used in plastic optical fiber data-rate transmission systems where transmission speeds are no more than 5-10 Mbit/s.